Reno,
Nelson Heat Tracing Systems makes a Self-Regulating Trace, which is listed for Class I Division 1 & 2.(Product Family of Reference = "Limitrace").
It is more like a Tube, rather than the normal "Flat Romex-Looking" Cable.
Heat Trace installed in Hazardous (Explosion Hazard) Areas must have Sheath Temperature that do not exceed the ignition Temperature of the Hazardous Gas (or Dust), which is present.
Use a GFPE type Circuit Breaker for the Branch Circuitry (specify 30ma threshold, not the 4-6ma Class A types).
--- However, from the Flash Fire you described earlier in this Thread, if there is a Leakage (Current) on the Heaters, you will be notified by a sudden Ball of Flame long before the GFPE Breaker trips!
G.E., Siemens, and Cutler-Hammer (Eaton) have Low Voltage MCCB (10KAIC @ 120V) type GFPE Devices - in both Single Pole and 2 Pole Units; with Trip Settings of 15, 20 and 30 Amps.
They look exactly like a Class A GFCI Circuit Breaker, so be aware when you receive the devices from your Distributor!
For G.E., they come in standard Plug-In "THQ" or Bolt-On "THQB" frames.
For Siemens, they come in "BL" and "BQ" frames.
I cannot remember the C-H frame type.
Have fun!
-- Scott
